Ember Knights Collab Reminder and Speedrun | Ember Knights v1.5 

you need to keep grinding and mostly choose rooms that are with embers and ash. I completed the doom run too with crossbow

one of the ways i also completed it was getting 2 main relics such as the Rejuvenation Glove & Ripe Elderberry. I went full crit+dmg build its slow but good enough. and skills i maxed out are the dice and cloak & dagger. with dice and those 2 relics your sorted

hopefully this will help you in your run

Like @jolwyndias903 Said, Make Sure to Enter Rooms that Reward Ember and Ash. After You Beat Praxis there will be More Efficient ways to Grind Ember, but For Now this is All You Got. Good Luck in Your Adventures

@@QuirkyTurtle3 I beat praxis on easy mode. Is it more worth it to grind easy mode all the way through or to up the difficulty and try to make it all the way through again